SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 21 Jan 2024: Pakistan 245.7 µg/m³, India 64.8 µg/m³ and China 44.3 µg/m³.
- 1Pakistan4 cities245.7
- 2India5 cities64.8
- 3China3 cities44.3
- 4Thailand62 cities, was 1041.9
- 5North Macedonia7 cities39.1
- 6Peru5 cities29.4
- 7Montenegro3 cities28.4
- 8Serbia12 cities, was 328.4
- 9Romania8 cities23.1
- 10Poland78 cities22.4
- 11Bulgaria6 cities22.0
- 12Greece10 cities21.3
- 13Italy22 cities18.9
- 14Chile43 cities18.5
- 15Czechia37 cities, was 3018.3
- 16Slovakia27 cities18.0
- 17Hungary9 cities17.7
- 18Norway21 cities16.9
- 19Hong Kong13 cities16.1
- 20Luxembourg3 cities15.9
+ 20 more countries, 15.5 µg/m³ and below
- 35United States764 cities6.8
Not counted on this day, too few cities measured: Singapore since 21 Jan 2024, Reunion since 15 Jan 2024, Malta since 2 Jan 2024 and Martinique since 1 Dec 2023.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.